Heavy crude oil is a highly viscous liquid that is solid or near solid at room temperature. With a high mass density and an API gravity of less than 20° API, there are numerous engineering challenges to extracting and processing heavy oil. In particular, the presence of high molecular weight hydrocarbon compounds such as asphaltenes contribute to the heaviness of heavy oil. Asphaltenes, which are soluble in alkanes (e.g. pentane and heptane), complicate production of heavy oil via normal methods (e.g. rod pumping) due to their tendency to agglomerate and precipitate, causing fouling in downhole pumps as well as the dumps and valves in surface process equipment.
These engineering challenges may be a deterrent to the production of heavy crude oil. However, as the price of regular crude oil increases, the economics for upgrading heavy oil to a synthetic crude oil continue to become favorable. Hence, much effort is being directed to the development of new technologies for commercial-scale applications of heavy crude oil extraction.
Blending is the established method of upgrading heavy oil, having been employed in the industry for more than 120 years. In this process, once heavy oil has been extracted and produced, it is de-watered and then blended with a locally-available lighter crude oil or condensate as a diluent to create “dilbit”. The dilbit is then sent to pipelines for transport, or it may be locally consumed in an upgrading process that converts non-transportable heavy oil into a lighter synthetic crude oil. This oil can subsequently be moved by pipeline and processed in conventional oil refineries.
There are numerous oil fields that contain extremely heavy and viscous oil which can become unproductive due to the cost and engineering challenges of extracting and producing heavy oil discussed above. In view of the foregoing, there exists a need to develop and implement methods and tools for the effective, efficient, and economic extraction and production of heavy crude oil.